Propagation channels may degrade a signal in various ways. To be able to recover transmitted information, the propagation channel may be estimated. Good channel estimation may enhance the possibilities to properly demodulate the signal and may increase the quantity of information which may be transmitted by a signal by using, for example, a more sophisticated modulation method.
In Wireless Local Area Network (WLAN) applications a radio signal may be transmitted over rather short communication distances. A 60 GHz WLAN system is currently studied by a task force of the Institute of Electrical and Electronics Engineers. A specification draft IEEE 802.11 ad is aimed at an indoor system with distances from under 1 m to several meters.